The VGM format is different from formats like NSF or SID, which contain the game's music code. Instead, the instructions sent to the sound chip are logged.

On November 20, 2005, VGM 1.50 was officially announced, and a new version of the input plug-in released. The new version of the format supported PCMoptimization for the Yamaha YM2612sound chip, which significantly reduces the size of VGM files by avoiding redundancy. The first YM2612 VGM archive, Project 2612, optimized all of its packages soon after.

1.
Video game
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A video game is an electronic game that involves interaction with a user interface to generate visual feedback on a video device such as a TV screen or computer monitor. The word video in video game referred to a raster display device. Some theorists categorize video games as an art form, but this designation is controversial, the electronic systems used to play video games are known as platforms, examples of these are personal computers and video game consoles. These platforms range from large mainframe computers to small handheld computing devices, the input device used for games, the game controller, varies across platforms. Common controllers include gamepads, joysticks, mouse devices, keyboards, the touchscreens of mobile devices, and buttons, or even, with the Kinect sensor, a persons hands and body. Players typically view the game on a screen or television or computer monitor, or sometimes on virtual reality head-mounted display goggles. There are often game sound effects, music and, in the 2010s, some games in the 2000s include haptic, vibration-creating effects, force feedback peripherals and virtual reality headsets. In the 2010s, the game industry is of increasing commercial importance, with growth driven particularly by the emerging Asian markets and mobile games. As of 2015, video games generated sales of USD74 billion annually worldwide, early games used interactive electronic devices with various display formats. The earliest example is from 1947—a Cathode ray tube Amusement Device was filed for a patent on 25 January 1947, by Thomas T. Goldsmith Jr. and Estle Ray Mann, and issued on 14 December 1948, as U. S. Written by MIT students Martin Graetz, Steve Russell, and Wayne Wiitanens on a DEC PDP-1 computer in 1961, and the hit ping pong-style Pong, used the DEC PDP-1s vector display to have two spaceships battle each other. In 1971, Computer Space, created by Nolan Bushnell and Ted Dabney, was the first commercially sold and it used a black-and-white television for its display, and the computer system was made of 74 series TTL chips. The game was featured in the 1973 science fiction film Soylent Green, Computer Space was followed in 1972 by the Magnavox Odyssey, the first home console. Modeled after a late 1960s prototype console developed by Ralph H. Baer called the Brown Box and these were followed by two versions of Ataris Pong, an arcade version in 1972 and a home version in 1975 that dramatically increased video game popularity. The commercial success of Pong led numerous other companies to develop Pong clones and their own systems, the game inspired arcade machines to become prevalent in mainstream locations such as shopping malls, traditional storefronts, restaurants, and convenience stores. The game also became the subject of articles and stories on television and in newspapers and magazines. Space Invaders was soon licensed for the Atari VCS, becoming the first killer app, the term platform refers to the specific combination of electronic components or computer hardware which, in conjunction with software, allows a video game to operate. The term system is commonly used

2.
Sega
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Nonetheless, Sega remains the worlds most prolific arcade producer, with over 500 games in over 70 franchises on more than 20 different arcade system boards since 1981. Sega, along with their sub-studios, are known for their multi-million selling game franchises, such as Sonic the Hedgehog, Virtua Fighter, Phantasy Star, Yakuza, Segas head offices are located in Tokyo. Segas North American division, Sega of America, is headquartered in Irvine, California, Segas European division, Sega Europe, is headquartered in London. After the war, the founders sold that company and established a new distributor called Service Games and this company provided coin-operated slot machines to U. S. bases in Japan and changed its name again to Service Games of Japan by 1953. David Rosen, an American officer in the United States Air Force stationed in Japan and this company eventually became Rosen Enterprises, and in 1957, began importing coin-operated games to Japan. On May 31,1960, Service Games Japan was closed, Three days later, two new companies were established to take over its business activities, Nihon Goraku Bussan and Nihon Kikai Seizo. By 1965, Rosen Enterprises grew to a chain of over 200 arcades, Rosen then orchestrated a merger between Rosen Enterprises and Nihon Goraku Bussan, becoming chief executive of the new company, Sega Enterprises, which derived its name from Service Games. Within a year, Sega began the transition from importer to manufacturer, with the release of the submarine simulator game, the game sported light and sound effects considered innovative for that time, eventually becoming quite successful in Japan. It was soon exported to both Europe and the United States, becoming the first arcade game in the US to cost 25 cents per play, in 1969, Rosen sold Sega to American conglomerate Gulf and Western Industries, although he remained as CEO following the sale. Under Rosens leadership, Sega continued to grow and prosper, and in 1974, Gulf and Western made Sega Enterprises, a subsidiary of an American company renamed Sega Enterprises, Inc. allowing them to take the companys stock public. Sega prospered heavily from the gaming boom of the late 1970s. In 1982, Segas revenues surpassed $214 million and that year they introduced the first game with isometric graphics, Zaxxon, the industrys first stereoscopic 3D game, SubRoc 3D, and the first laserdisc video game, Astron Belt. Astron Belt wasnt released in the U. S. until 1983, other notable games from Sega during this period are Head On, Monaco GP, Carnival, Turbo, Space Fury, Astro Blaster, and Pengo. In 1983-4, Sega published Atari 2600 versions of some of its arcade games, Carnival, Space Fury, Turbo, and Zaxxon were licensed to Coleco as launch titles for the ColecoVision console in 1982. Some of these and other titles were licensed to different companies for 8-bit computer versions, the Atari 8-bit computer port of Zaxxon is from Datasoft, for example, while the Commodore 64 port is from Synapse. An overabundance of games in 1983 led to the game crash. Seeking an alternate source of revenue from the arcade market, Sega designed and released its first home video game console. G&W sold the U. S. assets of Sega Enterprises that same year to pinball manufacturer Bally Manufacturing, nakayama became the new CEO of Sega, Robert Deith chairman of the board, and Rosen became head of its subsidiary in the United States

3.
Master System
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The Sega Master System is a third-generation home video game console that was manufactured by Sega. It was originally released in 1985 as the Sega Mark III in Japan, after being redesigned prior to its North American launch, the console was renamed Master System and released in 1986 in North America,1987 in Europe, and 1989 in Brazil. The redesigned Master System was also released in Japan in 1987 with additional features over the overseas models, the Master System also featured accessories such as a light gun and 3D glasses which were designed to work with a range of specially coded games. Succeeding the SG-1000, the Master System was released as a competitor to the Nintendo Entertainment System in the third generation of video game consoles. The Master System was constructed with hardware superior to that of the NES, however, it attained significantly more success in Europe and Brazil. The hardware of the Master System also shared similarities with Segas handheld game console. Sales of the console have been estimated between 10 and 13 million units, not including recent Brazil sales, compared to 62 million NES units sold, as of 2015, the Master System is the longest-lived game console, due to its popularity in Brazil. The company retained its Japanese subsidiary, Sega Enterprises, Ltd. as well as Segas North American research, with its arcade business in decline, Gulf and Western executives turned to Sega Enterprises, Ltd. s president, Hayao Nakayama, for advice on how to proceed. Nakayama received permission to proceed with project, leading to the release of Segas first home video game system. The SG-1000 was first released in Japan on July 15,1983 and it was launched on the same day that Nintendo released the Family Computer in Japan. Nakayama was then installed as CEO of the new Sega Enterprises, following the buyout, Sega released another console, the SG-1000 II, for ¥15,000. It featured a few hardware tweaks from the model, including detachable controllers. The SG-1000 II did not sell well, however, leading to Segas decision to work on the video game hardware used for the system. This resulted in the release of the Sega Mark III in Japan in 1985, engineered by the same internal Sega team that had created the SG-1000, the Mark III was a redesigned iteration of the previous console. The CPUs in the SG-1000 and SG-1000 II were Zilog Z80s running at 3.58 MHz, while the Mark III, the Mark III and Master System also carried over the Sega Card slot used in the SG-1000. According to Edge, lessons from the SG-1000s lack of success were used in the hardware redesign of the Mark III. The futuristic final design for the Master System was intended to appeal to Western tastes, the Sega Mark III was released in Japan in October 1985 at a price of ¥15,000. Despite featuring technically more powerful hardware than its competition, the Famicom

4.
Game Gear
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The Game Gear is an 8-bit handheld game console released by Sega on October 6,1990 in Japan,1991 in North America and Europe, and Australia in 1992. The Game Gear primarily competed with Nintendos Game Boy, the Atari Lynx and NECs TurboExpress. The handheld shares much of its hardware with the Master System and is able to play its own titles as well as those of the Master System, the latter being made possible by the use of an adapter. Containing a full-color backlit screen with a format, Sega positioned the Game Gear as a technologically superior handheld to the Game Boy. Though the Game Gear was rushed to market, its game library and price point gave it an edge over the Atari Lynx. However, due to issues with its battery life, lack of original titles, and weak support from Sega. The Game Gear was succeeded by the Genesis Nomad in 1995 and it was re-released as a budget system by Majesco in 2000, under license by Sega. Developed under the name Project Mercury, the Game Gear was first released in Japan on October 6,1990, in North America and Europe in 1991, and in Australia in 1992. Originally retailing at JP¥19,800 in Japan, US$149.99 in North America, and GB£99.99 in Europe, the Game Gear was developed to compete with the Game Boy, which Nintendo had released in 1989. The original Game Gear pack-in title was Columns, which was similar to the Tetris cartridge that Nintendo had included when it launched the Game Boy. With a late start into the gaming market, Sega rushed to get the Game Gear into stores quickly. Part of the intention of this move was to make Master System games easy to port to the Game Gear. With its quick launch in Japan, the handheld sold 40,000 units in its first two days,90,000 within a month, and the number of orders for the system was over 600,000. According to Sega of America marketing director Robert Botch, there is clearly a need for a quality system that provides features other systems have failed to deliver. This means easy-to-view, full-colour graphics and exciting quality games that appeal to all ages, before the Game Gears launch in 1990, Sega had success marketing its 16-bit home console, the Genesis, by advertising it as a more mature option for gamers. In keeping with this approach, Sega positioned the Game Gear as a grown-up option compared to the Game Boy. In North America, marketing for the Game Gear included side-by-side comparisons of Segas new handheld with the Game Boy, one Sega advertisement featured the quote, If you were color blind and had an IQ of less than 12, then you wouldnt mind which portable you had. Such advertising drew fire from Nintendo, who sought to have organized against Sega for insulting disabled persons

5.
Sega Genesis
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The Sega Genesis, known as the Mega Drive in most regions outside of North America, is a 16-bit home video game console which was developed and sold by Sega Enterprises, Ltd. The Genesis was Segas third console and the successor to the Master System, Sega first released the console as the Mega Drive in Japan in 1988, followed by a North American debut under the Genesis moniker in 1989. In 1990, the console was distributed as the Mega Drive by Virgin Mastertronic in Europe, by Ozisoft in Australasia, in South Korea, the systems were distributed by Samsung and were known as the Super Gam*Boy, and later the Super Aladdin Boy. The system supports a library of more than 900 games created both by Sega and an array of third-party publishers and delivered on ROM-based cartridges. It can play Master System games when the separately sold Power Base Converter is inserted, the Genesis has benefited from several peripherals and network services, as well as multiple first-party and third-party variations of the console that focus on extending its functionality. Controversy surrounding violent titles such as Night Trap and Mortal Kombat led Sega to create the Videogame Rating Council, Sega sold 30.75 million units worldwide. The console and its games continue to be popular among fans, game music fans, collectors. As of 2015, licensed third party re-releases of the console are being sold by AtGames in North America and Europe. Many games have been re-released in compilations for newer consoles and offered for download on online services, such as the Virtual Console, Xbox Live Arcade, PlayStation Network. The Genesis was succeeded by the Sega Saturn, in the early 1980s, Sega Enterprises, Inc. then a subsidiary of Gulf & Western, was one of the top five arcade game manufacturers active in the United States, as company revenues rose to $214 million. The company retained Segas North American R&D operation, as well as its Japanese subsidiary, Sega Enterprises, with its arcade business in decline, Gulf & Western executives turned to Sega Enterprises, Ltd. s president, Hayao Nakayama, for advice on how to proceed. Nakayama received permission to proceed with project, leading to the release of Segas first home video game system. The SG-1000 was not successful, and was replaced by the Sega Mark III within two years, Nakayama was then installed as CEO of the new Sega Enterprises, Ltd. In 1986, Sega redesigned the Mark III for release in North America as the Sega Master System and this was followed by a European release the next year. In 1987, Sega faced another threat to its business when Japanese computer giant NEC released the PC Engine amid great publicity. First announced in June 1988 in Beep, a Japanese gaming magazine, the developing console was referred to as the Mark V, but Sega management felt the need for a stronger name. After reviewing more than 300 proposals, the settled on Mega Drive. In North America, the name of the console was changed to Genesis, the reason for this change is not known, but it may have been due to a trademark dispute

6.
MSX
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Microsoft conceived the project as an attempt to create unified standards among various hardware makers of the period. They were popular mostly in Japan, and several other countries and it is difficult to estimate how many MSX computers were sold worldwide, but eventually 5 million MSX-based units were sold in Japan alone. The Metal Gear series, for example, was written for MSX hardware. The exact meaning of the MSX abbreviation remains a matter of debate, at the time, most people seemed to agree it meant MicroSoft eXtended, referring to the built-in Microsoft eXtended BASIC, specifically adapted by Microsoft for the MSX system. Another suggested source for the abbreviation was Matsushita-Sony, however, according to Kazuhiko Nishi, MSX could also stand for Machines with Software eXchangeability. In 1985, Kazuhiko Nishi told that he named MSX after the MX missile, the hardware design of these computers and the various dialects of their BASICs were incompatible. Other Japanese consumer electronics such as Panasonic, Canon, Casio, Yamaha, Pioneer. Nishi proposed MSX as an attempt to create an industry standard for home computers. Inspired by the success of VHS as a standard for video recorders, many Japanese electronic manufacturers along with GoldStar, Philips and Spectravideo built. Any piece of hardware or software with the MSX logo on it was compatible with MSX products of other manufacturers, in particular, the expansion cartridge form and function were part of the standard, any MSX expansion or game cartridge would work in any MSX computer. Nishis standard was built around the Spectravideo SV-328 computer, the standard consisted primarily of several off-the-shelf parts, the main CPU was a 3. This was a choice of components that was shared by other home computers and games consoles of the period, such as the ColecoVision home computer. To reduce overall system cost, many MSX models used a custom IC known as MSX-Engine, however, almost all MSX systems used a professional keyboard instead of a chiclet keyboard, driving the price up compared to the original SV-328. Consequently, these components alongside Microsofts MSX BASIC made the MSX a competitive, though somewhat expensive, the Japanese companies avoided the intensely competitive U. S. home computer market, which was in the throes of a Commodore-led price war. Only Spectravideo and Yamaha briefly marketed MSX machines in the U. S, by the time the MSX was launched in Europe, several more popular 8-bit home computers had also arrived, and it was far too late to capture the extremely crowded European 8-bit computer market. A problem for some software developers was that the method by which MSX-1 computers addressed their video RAM could be quite slow compared to systems that gave direct access to the video memory. Some minor compatibility issues also plagued ported Spectrum games, later games tended to use the MSX-1 joystick port or used MSXs official arrow keys and space bar, or offered the option to choose other keys with which to control the program, solving the problem. Moreover, the MSXs BIOS did not provide information either

7.
Neo Geo
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Neo Geo, stylised as NEO・GEO, also written as NEOGEO, is a family of video game hardware developed by SNK. On the market from 1990 to 2004, the brand originated with the release of a system, the Neo Geo MVS and its home console counterpart. Both the arcade system and console were powerful for the time, years later, SNK would release the Neo Geo CD, a more cost effective console with games released on compact discs. The console was met with limited success, due in part to its slow CD-ROM drive, in an attempt to compete with increasingly popular 3D games, SNK released the Hyper Neo Geo 64 arcade system in 1997 as the successor to its aging MVS. The system did not fare well and only a few games were released for it, a planned home console based on the hardware was never released. SNK later extended the brand by releasing two handheld consoles, the Neo Geo Pocket, and later Neo Geo Pocket Color, which competed with Nintendos Game Boy. Regardless of the failure of later Neo Geo hardware, games for the original MVS, in December 2012, SNK Playmore released a handheld console based on the original AES, the Neo Geo X. As of March 1997, the Neo Geo had sold 980,000 units worldwide, the Neo Geo Pocket Color also has been given praise for multiple innovations, and a very substantial library, despite its short life. SNKs first two using the Neo Geo name are an arcade system called the Neo Geo Multi Video System. The MVS offers arcade operators the ability to put up to six different arcade games into a single cabinet and it comes in many different cabinets but basically consists of an add on board that can be linked to a standard JAMMA system. The Advanced Entertainment System, originally known just as the Neo Geo, is the first video game console in the family, the hardware features comparatively colorful 2D graphics. The hardware was in part designed by Alpha Denshi, initially, the home system was only available for rent to commercial establishments, such as hotel chains, bars and restaurants, and other venues. When customer response indicated that some gamers were willing to buy a US$650 console, SNK expanded sales, the Neo Geo console was officially launched on 31 January 1990 in Osaka, Japan. The AES is identical to its counterpart, the MVS. The Neo Geo CD, released in 1994, was initially an upgrade from the original AES and this console uses CDs instead of ROM cartridges like the AES. The units 1X CD-ROM drive was slow, making loading times very long with the system loading up to 56 Mbits of data between loads, Neo Geo CD game prices were low at US$50, in contrast to Neo Geo AES game cartridges which cost as much as US$300. The system could also play Audio CDs, all three versions of the system have no region-lock. The Neo Geo CD was bundled with a control pad instead of a joystick like the AES, however, the original AES joystick can be used with all 3 Neo Geo CD models, instead of the included control pads

8.
Ad Lib, Inc.
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Today the AdLibs functionality can be recreated with emulators such as AdPlug and VDMSound. Emulating the AdLib Gold 1000 proves more of a due to the surround sound module. After development work on the ALMSC had concluded, Prevel struggled to engage the development community with his companys new product, needless to say, the Adlib hardware was not reaching its intended audience, developers with the PC gaming industry. Subsequently, Prevel engaged the assistance of Top Star Computer Services, Top Stars President, Rich Heimlich was sufficiently impressed by a product demonstration in Quebec in 1987 to endorse the product to his top customers. Sierra On-Lines Kings Quest IV became the first game-title to support the AdLib, the games high audio-production values, including a hired professional composer, riding on an already popular game-franchise, catapulted the AdLib card into mainstream media coverage. Soon, all game developers embraced the Adlib, hoping to give their software a competitive edge, on the retail-channel side, most retail stores chains and wholesale distributor were selling AdLib sound cards by 1990. The AdLib used Yamahas YM3812 sound chip which produces sound via FM synthesis, the AdLib card consisted of a YM3812 chip with off-the-shelf external glue logic to plug into a standard PC-compatible ISA 8-bit slot. PC software generated multitimbral music and sound effects through the AdLib card, digital audio was not supported, a key feature supported by later competition, particularly the Creative Labs Sound Blaster. The engineers who developed sound cards and software libraries for Ad Lib worked at Lyrtech, there are two separate revisions of the original AdLib sound card. AdLib did release a MicroChannel version of their original sound card, the AdLib MCA, notable updates for this MCA version was the use of a volume wheel, as the original potentiometer made the card too thick for the MCA standard. Ad Lib planned a new proprietary standard before releasing the 12-bit stereo soundcard called the AdLib Gold. The Gold 1000 used a later generation Yamaha YMF262 and 12-bit digital PCM capability while retaining compatibility with OPL2 through the OPL3 chip. The onboard Yamaha YMZ263-F also performs 2x oversampling, which would affect the OPL3 output slightly, a surround sound module was developed as an optional attachment that allowed a chorus-surround effect to be enabled for OPL3 outputs, however, only a few games supported it. One unique aspect is that it could be initialized for certain sounds, other optional attachments such as SCSI support and Modem support were in development as well. There is evidence of behavior by Creative in the failure of this card. Yamaha made parts for both Creative and AdLib with Creative being Yamahas biggest customer at the time, AdLibs Yamaha-created chip continually failed to pass testing while Creatives Yamaha chip passed. This enabled Creative to come to market first, shortly after which AdLibs chip passed testing, despite AdLibs efforts, the Gold 1000 failed to capture the market and the company eventually went bankrupt through cheaper alternatives such as the Creative Labs Sound Blaster 16. AdLib designed the Gold 1000 mainly in-house, as such, the Gold 1000s layout has a lot of discrete circuitry, Creative Labs was able to integrate their soundcards more tightly to reduce cost

9.
Sound Blaster
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By 1995 Sound Blaster cards had sold over 15 million units worldwide and accounted for seven out of ten sound card sales. The creator of Sound Blaster is the Singapore-based firm Creative Technology Limited, also known by the name of its United States subsidiary, the history of Creative sound cards started with the release of the Creative Music System CT-1300 board in August 1987. It contained two Philips SAA1099 circuits, which, together, provided 12 channels of square-wave bee-in-a-box stereo sound,4 channels of which can be used for noise and these circuits were featured earlier in various popular electronics magazines around the world. For many years Creative tended to use components and manufacturers reference designs for their early products. The various integrated circuits had white or black paper stickers fully covering their top thus hiding their identity, on the C/MS board in particular, the Philips chips had white pieces of paper with a fantasy CMS-301 inscription on them, real Creative parts usually had consistent CT number references. Surprisingly, the board contained a large 40-pin DIP integrated circuit, bearing a CT 1302A CTPL8708 serigraphed inscription. This chip allows software to detect the card by certain register reads. A year later, in 1988, Creative marketed the C/MS via Radio Shack under the name Game Blaster and this card was identical in every way to the precursor C/MS hardware. The Sound Blaster 1.0, CT1320A, was released in 1989, in addition to Game Blaster features, it had an 11-voice FM synthesizer using the Yamaha YM3812 chip, also known as OPL2. It provided perfect compatibility with the market leader AdLib sound card. Creative used the DSP acronym to designate the digital audio part of the Sound Blaster and this actually stood for Digital Sound Processor, rather than the more common digital signal processor, and was really a simple micro-controller from the Intel MCS-51 family. It could play back 8-bit monaural sampled sound at up to 23 kHz sampling frequency, the sole DSP-like features of the circuit were ADPCM decompression and a primitive non-MPU-401 compatibile MIDI interface. The ADPCM decompression schemes supported were 2 to 1,3 to 1 and 4 to 1, the CT1320B variety of the Sound Blaster 1.0 has C/MS chips installed in sockets rather than soldered on the PCB. Some sources note that the original Sound Blaster 1.0 was produced under the CT1310 number and this however is a topic of ongoing debate. Creative refers to CT1310 for the Sound Blaster 1.0 on its website, in spite of these limitations, in less than a year, the Sound Blaster became the top-selling expansion card for the PC. It achieved this by providing a fully AdLib-compatible product, with features, for the same. The inclusion of the port, and its importance to its early success, is often forgotten or overlooked. PCs of this era did not include a game port, Game port cards were costly and used one of the few expansion slots PCs had at the time

10.
Gzip
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Gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free replacement for the compress program used in early Unix systems. Version 0.1 was first publicly released on 31 October 1992, Gzip is based on the DEFLATE algorithm, which is a combination of LZ77 and Huffman coding. DEFLATE was intended as a replacement for LZW and other patent-encumbered data compression algorithms which, at the time, limited the usability of compress, although its file format also allows for multiple such streams to be concatenated, gzip is normally used to compress just single files. Compressed archives are created by assembling collections of files into a single tar archive. The final. tar. gz or. tgz file is called a tarball. Gzip is not to be confused with the ZIP archive format, various implementations of the program have been written. The most commonly known is the GNU Projects implementation using Lempel-Ziv coding, openBSDs version of gzip is actually the compress program, to which support for the gzip format was added in OpenBSD3.4. The g in this specific version stands for gratis and these implementations originally come from NetBSD, and supports decompression of bzip2 and the Unix pack format. The tar utility included in most Linux distributions can extract. tar. gz files by passing the z option, zlib is an abstraction of the DEFLATE algorithm in library form which includes support both for the gzip file format and a lightweight stream format in its API. The zlib stream format, DEFLATE, and the file format were standardized respectively as RFC1950, RFC1951. The gzip format is used in HTTP compression, a used to speed up the sending of HTML. It is one of the three formats for HTTP compression as specified in RFC2616. This RFC also specifies a zlib format, which is equal to the gzip format except that gzip adds eleven bytes of overhead in the form of headers and trailers. Still, the format is sometimes recommended over zlib because Microsoft Internet Explorer does not implement the standard correctly. Zlib DEFLATE is used internally by the Portable Network Graphics format, since the late 1990s, bzip2, a file compression utility based on a block-sorting algorithm, has gained some popularity as a gzip replacement. It produces considerably smaller files, but at the cost of memory, comparison of file archivers Free file format List of archive formats List of Unix programs GNU Gzip home page Original gzip Home Page

11.
Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing

12.
File manager
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A file manager or file browser is a computer program that provides a user interface to manage files and folders. Folders and files may be displayed in a tree based on their directory structure. Some file managers contain features inspired by web browsers, including forward, some file managers provide network connectivity via protocols, such as FTP, NFS, SMB or WebDAV. This is achieved by allowing the user to browse for a server or by providing its own full client implementations for file server protocols. A term that predates the usage of file manager is directory editor, the term was used by other developers, including Jay Lepreau, who wrote the dired program in 1980, which ran on BSD. This was in inspired by an older program with the same name running on TOPS-20. Dired inspired other programs, including dired, the editor script, file-list file managers are lesser known and older than orthodox file managers. One such file manager is flist, which was first used in 1981 on the Conversational Monitor System and this is a variant of fulist, which originated before late 1978, according to comments by its author, Theo Alkema. The flist program provided a list of files in the users minidisk, the file attributes could be passed to scripts or function-key definitions, making it simple to use flist as part of CMS EXEC, EXEC2 or XEDIT scripts. Orthodox file managers or command-based file managers are text-menu based file managers, Orthodox file managers are one of the longest running families of file managers, preceding Graphical User Interface-based types. Developers create applications that duplicate and extend the manager that was introduced by PathMinder, the concept is more than thirty years old—PathMinder was released in 1984, and Norton Commander version 1.0 was released in 1986. Despite the age of this concept, file managers based on Norton Commander are actively developed, and dozens of implementations exist for DOS, Unix, Nikolai Bezroukov publishes his own set of criteria for an OFM standard. An orthodox file manager typically has three windows, two of the windows are called panels and are positioned symmetrically at the top of the screen. The third is the line, which is essentially a minimized command window that can be expanded to full screen. Only one of the panels is active at a given time, the active panel contains the file cursor. Panels are resizable and can be hidden, files in the active panel serve as the source of file operations performed by the manager. For example, files can be copied or moved from the panel to the location represented in the passive panel. This scheme is most effective for systems in which the keyboard is the primary or sole input device, the active panel shows information about the current working directory and the files that it contains

13.
WinZip
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WinZip is a shareware file archiver and compressor for Windows, macOS, iOS and Android developed by WinZip Computing. It can create archives in Zip file format, and unpack some other file formats. Unpack BZ2, LHA, LZH, RAR, ZIP, 7Z, WinZip 1.0 was released in April 1991 as a graphical user interface front-end for PKZIP. Earlier in January 1991 Nico Mak Computing released a GUI front-end for OS/2 Presentation Manager called PMZIP and it used the OS/2 versions of the PKWARE, Inc. Originally released on CompuServe, availability of WinZip expanded across major online services, including GEnie, Prodigy, in 1993, WinZip announced the launch of its official support for customers on the Windows Utility Forum, serving over 100,000 members, providing updates and related information. By 1994, WinZip had become the official and required compression tool used by operators on CompuServe for forum file libraries. Starting from version 5.0 in 1993, the creators of WinZip incorporated compression code from the Info-ZIP project, from version 6.0 until version 9. This upgrade scheme was discontinued as of version 10.0, WinZip is available in standard and professional versions. However, the shell in Windows ME and later versions of Microsoft Windows has the ability to open and create. zip files, which reduces the need for extra compression software. On May 2,2006, Corel Corporation, best known for its WordPerfect and CorelDRAW product lines, WinZip 1.0 for Mac OS X was released in November 2010. This version is compatible with Mac OS X10.6 “Snow Leopard”, WinZip Mac Edition 2 includes support for OS X10.8 Mountain Lion. 128- and 256-bit key AES encryption in addition to the less secure PKZIP2.0 encryption method used in earlier versions, the AES implementation, using Brian Gladmans code, was FIPS-197 certified, on March 27,2003. However, Central Directory Encryption feature is not supported, support of additional compression methods, bzip2, PPMd, WavPack, LZMA, JPEG. Unicode support to ensure international characters are displayed for filenames in a Zip file, the ZIP file archive format was originally invented for MS-DOS in 1989 by Phil Katz. Seeing the need for an application with a Graphical User Interface, Nico Mak seized the opportunity. WinZip 1.0 was initial version for Windows, WinZip 2.0 added support for ARC files, support for self-extracting ZIP files, optional interface to Virus Scan software, dialog box to specify paths and filenames of external programs. WinZip 3.0 added full support for LZH files, including self-extracting LZH files, configurable support for most virus scanners, simplified options to add, WinZip 3.2 added Built-in ZIP Extraction so that PKUNZIP is not needed for most ZIP extract operations. WinZip always uses PKZIP. EXE to modify ZIP files, WinZip 4.0 added support for PKZIP2.0, including built-in ZIP extraction, support for the ARJ file format, new toolbar with descriptive pictorial buttons, added a 3-D look to all dialog boxes

14.
WinRAR
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WinRAR is a trialware file archiver utility for Windows. It can create and view archives in RAR or ZIP file formats, to enable the user to test the integrity of archives, WinRAR embeds CRC32 or BLAKE2 checksums for each file in each archive. WinRAR supports creating encrypted, multi-part and self-extracting archives, WinRAR and the RAR file format have evolved over time. Support for the archive format RAR5, using the same RAR file extension as earlier versions, was added in v5, WinRAR versions before 5.0 do not support RAR5 archives. AES encryption, when used, was increased from 128- to 256-bit, maximum path length for files in RAR and ZIP archives is increased to 2048 characters. The RAR5 file format removed comments for each file, authenticity verification, RAR5 also changed the file name for split volumes from archivename. rNN to archivename. partNN. rar. Packing of RAR or ZIP archives, unpacking of ACE, ARJ, BZIP2, CAB, EXE, GZ, ISO, JAR, LHA, RAR, TAR, UUE, XZ, Z, ZIP, ZIPX, 7z,001 archives. Checksum verification for ACE, ARJ, BZIP2, CAB, GZ, BZIP2, RAR, XZ, ZIP, when creating RAR archives, Support for maximum file size of 16 EiB minus 1. Compression dictionary from 1 MiB to 1 GiB, optional 256-bit BLAKE2 file hash can replace default 32-bit CRC32 file checksum. Optional encryption using AES with a 256-bit key, optional data redundancy is provided in the form of Reed-Solomon recovery records and recovery volumes, allowing reconstruction of damaged archives. Optional Quick Open Record to open RAR files faster, Ability to create multi-volume archives Ability to create self-extracting files. The self-extractor can execute commands, such as running a specified program automatically after self-extraction, Support for advanced NTFS file system options, such as NTFS hard and symbolic links. Support for maximum path length up to 2048 characters, optional file time stamp preservation, creation, last access, high precision modification times. The software is distributed as try before you buy, it may be used without charge for 40 days, in China, a completely free-to-use personal edition has been provided officially since 2015. It was widely reported that WinRAR v5. exe labelled as self-extracting archive, then you can trick them into running your smuggled JavaScript. Command line RAR and UNRAR were first released in autumn 1993, early development version WinRAR1. 54b was released in 1995 as 16-bit Windows 3. x application. Version 2.00 was released on September 6,1996, since version 3.00, the new RAR3 archive format is implemented. The new compressed archives cannot be managed by old versions of WinRAR, since version 3.41, WinRAR adds support for Linux. Z archives like GZIP and BZIP2

15.
MOS Technology SID
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The MOS Technology 6581/8580 SID is the built-in Programmable Sound Generator chip of Commodores CBM-II, Commodore 64, Commodore 128 and Commodore MAX Machine home computers. It was one of the first sound chips of its kind to be included in a computer prior to the digital sound revolution. Together with the VIC-II graphics chip, the SID was instrumental in making the C64 the best-selling computer in history, patent 4,677,890, which was filed on February 27,1983, and issued on July 7,1987. The patent expired on July 7,2004, the SID was devised by engineer Robert Bob Yannes, who later co-founded the Ensoniq digital synthesizer company. Yannes headed a team that included himself, two technicians and a CAD operator, who designed and completed the chip in five months, Yannes was inspired by previous work in the synthesizer industry and was not impressed by the current state of computer sound chips. Instead, he wanted a high-quality instrument chip, which is the reason why the SID has features like the envelope generator, emphasis during chip design was on high-precision frequency control, and the SID was originally designed to have 32 independent voices, sharing a common oscillator. Another feature that was not incorporated in the design was a frequency look-up table for the most common musical notes. The support for an input pin was a feature Yannes added without asking. The masks were produced in 7-micrometer technology to gain a high yield, the chip, like the first product using it, was finished in time for the Consumer Electronics Show in the first weekend of January 1982. Even though Yannes was partly displeased with the result, his colleague Charles Winterble said, the specifications for the chip were not used as a blueprint. Rather, they were written as the development work progressed, Yannes claims he had a feature-list of which three quarters made it into the final design. This is the reason why some of the specifications for the first version were accidentally incorrect, the later revision was revised to match the specification. For example, the 8580 expanded on the ability to perform a binary AND between two waveforms, something that the 6581 could only do in a limited and unintuitive manner. Another feature that differs between the two revisions is the filter, the 6581 version is far away from the specification, since 6581 and 8580 SID ICs are no longer produced, they have become highly sought after. In late 2007, various defective chips started appearing on eBay as supposedly new, all of these remarked SIDs have a defective filter, but some also have defective channels/noise generators, and some are completely dead. The different filter modes are sometimes combined to produce additional timbres, three attack/decay/sustain/release volume controls, one for each audio oscillator. Oscillator sync for each audio oscillator, two 8-bit A/D converters external audio input random number/modulation generator The SID is a mixed-signal integrated circuit, featuring both digital and analog circuitry. All control ports are digital, while the ports are analog

16.
Pulse-code modulation
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Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the form of digital audio in computers, compact discs, digital telephony. In a PCM stream, the amplitude of the signal is sampled regularly at uniform intervals. Linear pulse-code modulation is a type of PCM where the quantization levels are linearly uniform. This is in contrast to PCM encodings where quantization levels vary as a function of amplitude, though PCM is a more general term, it is often used to describe data encoded as LPCM. Early electrical communications started to sample signals in order to interlace samples from multiple telegraphy sources, the American inventor Moses G. Farmer conveyed telegraph time-division multiplexing as early as 1853. Electrical engineer W. M. Miner, in 1903, used an electro-mechanical commutator for time-division multiplexing multiple telegraph signals and he obtained intelligible speech from channels sampled at a rate above 3500–4300 Hz, lower rates proved unsatisfactory. This was TDM, but pulse-amplitude modulation rather than PCM, in 1920 the Bartlane cable picture transmission system, named after its inventors Harry G. Bartholomew and Maynard D. In 1926, Paul M. Rainey of Western Electric patented a machine which transmitted its signal using 5-bit PCM. The machine did not go into production, british engineer Alec Reeves, unaware of previous work, conceived the use of PCM for voice communication in 1937 while working for International Telephone and Telegraph in France. He described the theory and advantages, but no practical application resulted, Reeves filed for a French patent in 1938, and his US patent was granted in 1943. By this time Reeves had started working at the Telecommunications Research Establishment, the first transmission of speech by digital techniques, the SIGSALY encryption equipment, conveyed high-level Allied communications during World War II. In 1943 the Bell Labs researchers who designed the SIGSALY system became aware of the use of PCM binary coding as already proposed by Alec Reeves. In 1949 for the Canadian Navys DATAR system, Ferranti Canada built a working PCM radio system that was able to transmit digitized radar data over long distances, PCM in the late 1940s and early 1950s used a cathode-ray coding tube with a plate electrode having encoding perforations. The plate collected or passed the beam, producing current variations in binary code, rather than natural binary, the grid of Goodalls later tube was perforated to produce a glitch-free Gray code, and produced all bits simultaneously by using a fan beam instead of a scanning beam. Patent 2,801,281 filed in 1946 and 1952, another patent by the same title was filed by John R. Pierce in 1945, and issued in 1948, U. S. The three of them published The Philosophy of PCM in 1948, PCM is the method of encoding generally used for uncompressed audio, although there are other methods such as pulse-density modulation. The 4ESS switch introduced time-division switching into the US telephone system in 1976, LPCM is used for the lossless encoding of audio data in the Compact disc Red Book standard, introduced in 1982

17.
Yamaha YM2612
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OPN2, is a six-channel sound chip developed by Yamaha. It belongs to Yamahas OPN family of FM synthesis chips used in several game, developed as a stripped-down version of the YM2608, it lacks its larger siblings ADPCM channel, Rhythm Sound System, SSG components, and GPIO ports. It also includes a sound mixer with integrated DAC. It was also available in CMOS form, as the YM3438 and it was most notably used in Segas Mega Drive/Genesis video game console, as well as Fujitsus FM Towns computer series. As with the YM3438, it was used by Sega in various game systems, including the Mega-Play, System 18. The DAC in the YM2612 introduces a glitch in the edge of waveforms, shifting that side out of place. This has become known among fans as the ladder effect, post-YM2612 sound filtering circuitry varied in degree and quality between devices using the YM2612, affecting the sound quality even further. Along with the changes, the chip was stripped of its predecessors SSG component. Whereas the high-end OPN chips have dedicated ADPCM channels for playing sampled audio, however, its sixth channel can act as a surrogate PCM channel by means of the DAC Enable register, allowing the chip to play 8-bit PCM sound samples. This replaces FM output for that channel, PCM data is written to the channel via an 8-bit register. Unlike the other OPNs with ADPCM, the YM2612 does not provide any timing or buffering of samples, so all frequency control, OPN2C, the CMOS form of the YM2612, changed the Channel 6 DAC output to the same 9-bit output in FM mode. The chip also had higher output impedance, requiring heavier external noise filtering circuitry, Sega used an improved version of the OPN2C for the Model 2 version of the Mega Drive/Genesis, which uses a modified internal DAC that produces considerably less ladder effect distortion. Yamaha YM2608 Yamaha YM2203 Sound chip VGM Chipdir The infamous SEGA2. DOC spritesmind. net – New Documentation, An authoritative reference on the YM2612 YM3438 Application Manual

MOS Technology SIDs. The right chip is a 6581 from MOS Technology, known at the time as the Commodore Semiconductor Group (CSG.) The left chip is an 8580, also from MOS Technology. The numbers 0488 and 3290 are in WWYY form, i.e. the chips were produced week 4 1988 and week 32 1990. The last number is assumed to be a batch number.